Human hair becomes soiled due to its contact with the surrounding environment and from the sebum secreted by the scalp. The soiling of hair causes it to have a dirty feel and an unattractive appearance. The soiling of the hair necessitates shampooing with frequent regularity.
Shampooing cleans the hair by removing excess soil and sebum. However, shampooing can leave the hair in a wet, tangled, and generally unmanageable state. Once the hair dries, it is often left in a dry, rough, lusterless, or frizzy condition due to removal of the hair's natural oils and other natural conditioning and moisturizing components. The hair can further be left with increased levels of static upon drying, which can interfere with combing and result in a condition commonly referred to as "fly-away hair."
A variety of approaches have been developed to alleviate these after-shampoo problems. These approaches range from post-shampoo application of hair conditioners such as leave-on and rinse-off products, to hair conditioning shampoos which attempt to both cleanse and condition the hair from a single product. Hair conditioners are typically applied in a separate step following shampooing. The hair conditioners are either rinsed-off or left-on, depending upon the type. Of product used. Hair conditioners, however, have the disadvantage of requiring a separate and inconvenient treatment step. Conditioning shampoos, i.e. shampoos which both cleanse and condition the hair, are highly desirable products because they are convenient for consumers to use.
In order to provide hair conditioning benefits in a cleansing shampoo base, a wide variety of conditioning actives have been proposed. However, many of these actives have the disadvantage of leaving the hair feeling soiled or coated, of interfering with the cleansing efficacy of the shampoo.
Japanese Patent Laid-open (Kokai) H6-17097 published Jan. 25, 1994 discloses cleaning compositions such as shampoos comprising a polyvalent metal salt of anionic surfactant and a silicone derivative. Exemplified anionic surfactants include acyl amino acid salts. International Publication No. WO95/01152 published Jan. 12, 1995 discloses a hair conditioning shampoo comprising a detersive surfactant, a nonvolatile hair conditioning agent, and polyvalent metal cations in free ion form. Japanese Patent Laid-open (Kokai) H7-11287 published Jan. 13, 1995 discloses a cleaning composition such as shampoos comprising an N-acyl neutral amino acid magnesium salt and an anionic surfactant. Exemplified amino acid moieties of the magnesium salt are N-methyl-.beta.-alanine and sarcosine.
In the present invention, a hair conditioning shampoo composition comprising a primary anionic surfactant, a polyvalent metal cation and a cationic conditioning agent has been developed. This composition provides conditioning shampoo compositions which have improved overall conditioning benefits, improved lathering, and preferable viscosity.